<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<！-- 代码段中变量的作用域只能在代码段中-->
		<script>
			let x=10
			console.log(x)
			{let x=100
			console.log(x)
			}
			
			console.log(x)
		</script>
	</head>
	<body>
	</body>
</html>
